Hyderabad

You can get the detailed report below:
http://www.manage.gov.in/pgdmABM/students.asp

Sikkim Manipal University is quite reputed, and so is Symbiosis. You place will not matter in case of distance education, if that institute has a learning center branch in your city.

Yes, it is a good idea. There are many institutes offering Diploma in aviation, but in order to pursue MBA in aviation management, I would suggest you to go for AIMFILL International HYD.

The admission in any of the NMIMS campus is based on two rounds 1. NMAT score wherein a cut off mark is declared for each campus. It is usually 208-210 fro mumbai, 190 -195 for bangalore and hyderabad. If you clear the cut off the you are called for the next round. 2. CD-PI round - this happens at Mumbai campus and after this the final shortlist is declared for each campus.

Marketing is the most recommended and accepted.
https://www.shiksha.com/mba/colleges/distance-correspondence-mba-colleges-in-hyderabad

You need to clear your 12th standard with atleast 50% marks in biology, physics and chemistry including practicals. You should have passed each subject separately. A Common Entrance Test (CET) is carried out for selecting the aspirants.